From 317b9549a217e552bf8aa314a6d6f46b532c6a8a Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Wed, 3 Mar 2021 03:06:30 +0100
Subject: lib: add compose

---
 lib/default.nix | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'lib')

diff --git a/lib/default.nix b/lib/default.nix
index 2efeec07..4190f8f5 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -15,6 +15,10 @@ let
     uri = import ./uri.nix { inherit lib; };
     xml = import ./xml.nix { inherit lib; };
 
+    # compose a list of functions to be applied from left to right, i.e.
+    # compose :: [ (xm -> xn) ... (x1 -> x2) (x0 -> x1) ] -> x0 -> xn
+    compose = foldl' (f: g: x: f (g x)) id;
+
     eq = x: y: x == y;
     ne = x: y: x != y;
     mod = x: y: x - y * (x / y);
-- 
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